Multi-axis sensors may be used for inertial sensing of motion in three dimensions. Such sensors may be constructed of relatively large and expensive electromagnetic and optical devices. More recently, micromechanical sensors have been fabricated using semiconductor processing techniques. Micro electrical mechanical systems (MEMS) allow formation of physical features using established semiconductor materials and processing techniques. These techniques enable the physical features to have relatively small sizes and be precise. Specifically, micromechanical accelerometers and gyroscopes have been formed from silicon wafers using photolithographic and etching techniques. Such microfabricated sensors hold the promise of large scale production and lower cost.
Vibratory microgyroscopes (xe2x80x9cmicrogyrosxe2x80x9d) have been produced using MEMS processing techniques. In a vibratory gyroscope, the Coriolis effect induces energy transfer from a driver input vibratory mode to another mode which is sensed or output during rotation of the gyroscope. Silicon micromachined vibratory microgyros may be integrated with silicon electronics. These devices are capable of achieving high quality (Q) factors, can withstand high xe2x80x9cgxe2x80x9d shocks due to their small masses, are relatively insensitive to linear vibration, and consume little power. However there are several limitations to the current construction method that hinders its mass producability, specifically each microgyro must have a post inserted and bonded individually to function.
A vibratory microgyroscope may include an upper gyroscope section bonded to a lower gyroscope section. Each gyroscope section may include resonator petals, electrodes, and an integrated half post. The half posts are aligned and bonded to act as a single post.
The gyroscope sections may have a symmetrical design, each include three resonator petals alternating with three electrode sections. The electrodes sections may include drive and sense electrodes for driving and sensing rocking modes, respectively. Each gyroscope section may include a hub connected to an outer ring by spring members. The hub may support the resonator petals and the integrated half post.
The vibratory microgyroscope may be a micro electrical mechanical system (MEMS) device fabricated from silicon-on-insulator (SOI) wafer(s) using semiconductor processing techniques.